Heterogeneous Oxidation of Secondary Organic Tracers of Isoprene and Toluene by Ozone

: For this paper, chamber experiments were carried out to investigate the oxidation of secondary organic tracers of toluene and isoprene by ozone under different conditions (relative humidity, mixing state, etc.) using a relative rate constants approach. The uncertainty of the tracer-based method due to the ozone oxidation of secondary organic tracers was also addressed. The results showed that the effective rate constants of analogue of 2-methyl erythritol (AME) and 2,3-dihydroxy-4-oxopentanoic acid (DHOPA) were (4.60±0.66)×10-19 cm3·(molecule·s)-1and (6.57±0.51)×10-19 cm3·(molecule·s)-1, respectively. Given the instability of the secondary organic tracers caused by the oxidation, the contributions of toluene and isoprene to secondary organic aerosols could be underestimated by 16.5%-44.8% and 18.3%-47.3%, respectively.